This is a single-arm observational longitudinal study in of patients with metastatic castrate-resistant prostate cancer designed to assess the longitudinal trajectory of pain and other symptoms. The study aims to address several key methodological questions that will inform the design of future clinical trials with symptom endpoints in this population, including: the definition of "clinically meaningful" pain; criteria for concluding a clinically meaningful pain reduction; criteria for concluding clinically meaningful pain progression; reliable methods quantifying analgesic use (given that "equianalgesic tables" and "point scoring systems" are generally considered unreliable by pain researchers and regulatory agencies , , ); ideal recall periods for pain questions; tradeoffs of different frequencies of symptom reporting; symptom trajectories over time; and associations of pain scores with other metrics used in prostate cancer research (imaging, PSA values, circulating tumor cells, etc).
